This investigation proposes to carry out a two-stage procedure for psychiatric case identification and classification of children and adolescents in the 4-16 age group in the island of Puerto Rico. The proposal assumes that the period of data collection can be coupled with the adult psychiatric epidemiology study (RMH #36230) which is scheduled to be January-June 1984, in order to study the relationship between child psychopathology and an adult with psychopathology in the same household. This study could be carried out at another point in time but without this feature and at a somewhat higher cost than what is being proposed. The study would utilize the Master Sample Survey of the Health Department of Puerto Rico. This is a stratified multistage probability sample of dwelling units covering the civilian non-institutional population of Puerto Rico. The first stage of the study would administer a screening instrument (The Child Behavior Checklist of Achenbach and Edelbrock) for the purposes of case finding to a representative sample (N=1,200-1,500 children). The second stage would obtain direct clinical psychiatric diagnoses on positive cases (estimated N=120-180 children) as well as on a sample of negative cases (N=60) in order to test the adequacy of the screening instrument. The second stage would provide measures of prevalence and a psychiatric diagnostic profile of Puerto Rican children. Additional global measures of adaptive functioning will be obtained in the second stage by means of the Children's Global Assessment Scale (C-GAS). This will provide a measure of severity of functional impairment. It is anticipated that the data obtained in this study will be useful for planning the scope and type of mental health facilities that need to be developed for Puerto Rico's children, as well as to provide an epidemiological data base for comparative purposes in future investigations in Puerto Rico as well as in the mainland.